Conventionally, barrier layers for use in pneumatic tires are made out of butyl or halogenated butyl rubber to inhibit the loss of air or oxygen therethrough, such as to maintain pressure over extended periods of time. Often times, however, to use these butyl rubber-based materials, an additional rubber layer, e.g., a tie layer, with low hysteresis loss is sandwiched between the barrier layer, e.g., an innerliner, and the carcass or plies of the tire. This additional tie layer undesirably increases the weight of the innerliner system. To that end, new low gas permeability materials for use in barrier layers have recently been developed that can replace conventional butyl rubber-based materials. One example of the newer materials, which has been developed for use as tire barrier layers, includes undrawn polymeric films. Another example includes dynamically-vulcanized alloys (DVAs), which can include mixtures of thermoplastic resins, elastomers and, optionally, a binder resin to enhance the compatibility between the two. Advantageously, these newer, low gas permeable materials are markedly thinner than their conventional butyl rubber-based counterparts, which provide a substantial weight savings. However, there are still drawbacks to overcome with the new materials.
For example, these new materials often demonstrate poor tack, poor adhesion to self after curing, and poor adhesion to other conventional tire layer materials used in building tires, such as ply rubber. These challenges are often addressed by the appropriate selection of adhesives, which can be applied to the surface(s) of the barrier layer. However, this adds extra material and processing steps, and thus, extra costs to the manufacturing process. In addition, for non-cylindrical panels of barrier layers, the ends, which must be secured together, are oftentimes the source of failure, as is described in Kaido et al., U.S. Pat. No. 5,938,869. For example, for simple overlap junctions, a lap joint may separate upon tire inflation and also can introduce substantial amounts of non-uniformity at the overlap joints.
Accordingly, there remains a need for a pneumatic tire with a barrier layer, and a method of making the same, that overcomes the aforementioned drawbacks and disadvantages.